Field of the Invention
This invention relates to drilling in earth formations located beneath a body of water, such as in the Gulf of Mexico, and in which the drilling operations are conducted from a floating structure. More specifically, this invention relates to a method and apparatus involving a riser pipe which extends from the ocean floor to the floating vessel located at the surface of the body of water. It relates especially to a novel riser pipe in which there are means for varying the effective size of the riser.